Tool for driving fasteners

ABSTRACT

A tool is provided for driving fasteners, such as nails, screws and the like, into a workpiece. The tool has a guide with a forwardly opening bore containing a fastener driving spindle which is longitudinally movable in the bore in a forward driving stroke and a rearward retraction stroke. The fasteners are prepackaged in a friable carrier strip to which the fasteners are secured in spaced relation and which is fed endwise into the guide bore following each retraction stroke of the tool spindle to locate the currently leading fastener on the strip in coaxial driving position within the bore in front of the spindle. During each forward driving stroke, the spindle shears and fragments the leading end of the carrier strip to release the leading fastener and drive the latter forwardly into a workpiece.

United States Patent [72] Inventor Donald B. Halstead 278 Foxbury Ave.,Pomona, Calif. 91767 211 Appl. No. 735,420 [22] Filed June 7, 1968 [45]Patented Jan. 12, 1971 [54] TOOL FOR DRIVING FASTENERS 5 Claims, 7Drawing Figs.

[52] U.S.Cl. 144/32, 206/56, 227/136 [51] Int. Cl. 1325b 23/00 [50]Field of Search 144/32; 206/56DF, (Inquired); 227/136, (Inquired) [36]References Cited I UNITED STATES PATENTS 2,152,977 4/1939 Schindell44/32X 2,878,700 3/1959 Reynolds... 144/32X 2,943,652 7/1960 Chilton144/32 3,152,334 10/1964 Lingle 206/56 3,212,632 10/1965 Baum et a1.206/56 10/ 1965 Dickson 206/56 Primary ExaminerGerald A. DostAttorney-Boniard I. Brown ABSTRACT: A tool is provided for drivingfasteners, such as nails, screws and the like, into a workpiece. Thetool has a guide with a forwardly opening bore containing a fastenerdriving spindle which is longitudinally movable in the bore in a forwarddriving stroke and a rearward retraction stroke. The fasteners areprepackaged in a friable carrier strip to which the fasteners aresecured in spaced relation and which is fed endwise into the guide borefollowing each retraction stroke of the tool spindle to locate thecurrently leading fastener on the strip in coaxial driving positionwithin the bore in front of the spindle. During each forward drivingstroke, the spindle shears and fragments the leading end of the carrierstrip to release the leading fastener and drive the latter forwardlyinto a workpiece.

PATENTED Jun 2191|- sum 1 or 2 lNl/EA/TOE llrllllll I'll LELrFE TOOL FORDRIVING FASTENERS BACKGROUND OF THE INVENTION The invention relates moreparticularly to such a tool wherein the fasteners are prepackaged inacarrier strip which is fed endwise to the tool to successively locatethe fasteners in driving position in from front of a fastener drivingspindle, and wherein further the spindle is movable through a drivingstoke in such a way as to separate from the carrier strip and drive intoa workpiece the fastener currently in driving position.

2. Prior Art The present invention is concerned generally with fastenerdriving tools of the class having a fastener driving spindle which islongitudinally movable through a forward driving stroke and a rearwardretraction stroke, and infeed means for feeding the fasteners to bedriven in succession to a driving position in front of the spindle whenthe latter is retracted. During each driving stroke, the spindle engagesthe fastener currently in driving position and drives the fastenerforwardly from the tool into a workpiece. Tools of this class are 'wellknown in the art and are used to drive nails, screws, and other types offasteners. The existing tools, while widely diverse in construction andoperation, are subject to certain common deficiencies which detract fromtheir usefulness. Foremost among these deficiencies are complexity ofconstruction, high cost of manufacture, and tendency to jamming andother forms of malfunction. These deficiencies result, in large part,from the types of fastener infeed actions which are employed in thetools. Thus, many of the existing tools utilize an infeed actioninvolving feeding of totally discrete or unattached fasteners. Examplesof tools utilizing such a fastener infeed action are found in U.S. Pat.Nos. 2,943,652; 3,157,884; 3,294,130 and 2,770,269. This type of infeedaction necessitates the use of relatively complex and costly infeedmechanisms for advancing the fasteners in succession to the tool, gatingthe fasteners in succession to driving position, and releasably holdingthe fasteners in driving position until driven.

Another type of fastener infeed action which is employed in somefastener driving tools of the kind under discussion involves the use ofprepackaged fasteners that are preassembled in a strip pack including acarrier strip to which the fasteners are secured in spaced relation.During operation of such tools, the fastener strip is fed endwise to thetool intermittentlyin timed relation to the reciprocating motion of thefastener driving spindle. By way of example, U.S. Pat. No. 2,009,580discloses a fastener driving tool of this kind. The existing tools ofthis type are commonly characterized, again, by a strip infeed mechanismwhich is relatively complex in construction, costly to manufacture,prone to malfunction, and otherwise not totally satisfactory.

SUMMARY OF THE INVENTION The present invention provides a fastenerdriving tool of the general class described having an improved striptype fastener infeed action and mechanism. The infeed mechanism ischaracterized by optimum simplicity of construction, economy ofmanufacture, immunity to jamming and other types of malfunction, andother highly desirable features of construction and operation. Ingeneral terms, the present tool is characterized by a guide having abore in which is longitudinally movable the fastener driving spindle.The fasteners to be driven are prepackaged in a strip pack including afriable or fragile strip to which the fasteners are secured inlongitudinally spaced relation. Infeed means are provided on the toolfor feeding the carrierstrip. endwise into the guide bore, laterally ofthe bore, each time the spindle retracts to locate the currently leadingfastener on'the strip in coaxial driving position within the guidebore,-in front of the spindle. In the particular embodiment of theinvention which has been selected for presentation in this disclosure,the infeed means comprises an infeed magazine which contains thefastener carrier strip and a spring loaded follower behind the strip forconstantly urging or pushing the strip forwardly through the magazineinto the guide bore. During each forward driving stroke, the spindleshears and fragments a leading portion of the carrier strip within theguide bore to release from the strip the fastener currently in drivingposition and then drive this fastener forwardly into the workpiece.

The tool has other unique features which particularly adapt the tool toits intended uses. One of these features resides in the fact that theinfeed magazine is relatively simple and quick to reload by the tooloperator, such that the reloading procedure does not delay operation ofthe tool for any appreciable length of time. Another feature of the toolresides in extended work-engaging members or feet which may be used onthe tool to permit driving of relatively long fasteners, and whereinviewing slots are provided to facilitate the accurate positioning orspotting of fasteners, particularly with respect to predrilled holes.According to yet another and highly im portant feature of the invention,the fastener driving'structure of the tool, that is, the tool guide,driving spindle, and infeed magazine, are constructed in the form of anattachment or adapter that may be applied to a conventional motorizedspindle actuator or driver. The particular embodiment of the inventionwhich has been selected for illustration in this disclosure, forexample, is a self-feeding screw driver attachment or adapter for aconventional hand drill motor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary side elevationof the present fastener driving tool, in this instance a screw driver;

FIG. 2 is a fragmentary longitudinal section through the lower portionof the tool in FIG. 1;

FIG. 3 is a section taken on line 3-3 in FIG. 1;

FIG. 4 is a view looking in the direction of the arrow 4in FIG. 1;

FIG. 5 is an enlarged section taken on line 5-5 in FIG. 1; FIG. 6 is anenlarged fragmentary perspective view of a portion of the tool guide;and

FIG. 7 is an enlarged fragmentary longitudinal section through amodified fastener driving tool according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In general terms, the inventionprovides a tool, represented in the drawings by the tool 10, for drivingfasteners 12 into a workpiece 14. The tool has a guide 16 with front andrear ends and a longitudinal bore 18 opening through these ends. Movablewithin the bore 18 is-a fastener driving spindle 20. Means 22 areprovided for moving the spindle longitudinally relative to the guidethrough alternate rearward retraction strokes and forward drivingstrokes. According to a unique and highly important feature of theinvention, the fasteners 12 are prepackaged in a strip pack 24. Thisstrip pack includesa relatively longitudinally rigid fastener carriertape or strip 26 to which the fasteners 12 are secured in longitudinallyspaced relation with the axes of the fasteners extending laterally ofthe strip. In the particular embodiment of 'the invention illustrated,the fasteners extend at a slight angle to the stfip for reasons to beexplained presently. The tool is equipped with infeed means 28 forfeeding the carrier strip 26 endwise into the guide bore 18, through oneside of the bore, following each retraction stroke of the tool spindle20 to locate the currently leading fastener 12 on the strip in coaxialdriving position within the bore in front of the tool spindle, as shownin FIG. I. During the following forward driving stroke of the spindle,the latter engages the. fastener in driving position, separates thisfastener from the carrier strip, and drives the fastener forwardly fromthe guide bore into the workpiece 14.

Referring now in more detail to the inventive embodiment which has beenselected for illustration, the fasteners 12 shown are screws, and theillustrated fastener driving tool is a motorized screw driver whereinthe spindle is both moved longitudinally and driven in rotation to drivethe screws 12 into the workpiece 14. In this instance, the means 22 formoving the spindle through its driving and retraction strokes comprisesa conventional motorized hand drill 30 including a body 32 which housesa motor (not shown). The tool body also has a hand grip (not shown) bywhich the tool may be held. Extending from the front end of the toolbody is a motor driven shaft 34. The protruding front end of this shaftis commonly surrounded by a threaded shoulder or collar 36 on the toolbody 32.

The actual fastener driving structure 38 of the present inventionconstitutes an adapter or attachment which may be secured to theconventional motorized hand drill 22. This adapter or attachmentincludes the guide 16, spindle 20, and fastener infeed means 28. Guide16 has two telescopically interfitting sleeves 40.and 42. In thisinstance, the upper or rear sleeve 40 is polygonal in external crosssection and fits slidably within the lower or font sleeve 42. Thesleeves are joined by a screw 44 which is threaded in the sleeve 40 andextends through a slot 46 in the sleeve 42 to limit relativelongitudinal movement of the sleeves. The upper end of the rear sleeve40 is internally threaded for connection to the threaded collar 36 onthe tool body 32, thus to releasably secure the fastener driving adapteror attachment 38 to the body. Secured by screws 48 to the front end ofthe front sleeve 42 is a tip member 50 which contains the guide bore 18.This guide bore is located on a common axis of the sleeves 40, 42 andopens upwardly to the interior of the sleeves and downwardly through thelower face of the tip member. Face 52 is inclined at an acute anglerelative to the common axis of the sleeves 40, 42, for reasons to appearpresently. In this instance, the guide bore 18 is formed by a bearinginsert 54 which is fixed within a bore in the tip member 50. Actingbetween the sleeves 40, 42 is a coil spring 56 which urges the sleevesapart to their positions of FIG. 1.

The lower end of the fastener driving spindle 20 fits slidably androtatably within the guide bore 18 and, in this instance, is providedwith a screw driver tip 58. The spindle extends upwardly through abearing bore 60 in the front end of the rear sleeve 40 to the upper endof the latter sleeve. Fixed to the upper end of the spindle is a clutchcollar 62. This clutch collar is contained within a counterbore 64 atthe upper end of the rear sleeve. The counterbore contains a secondclutch collar 66 which is secured to the motor shaft 34. Collars 62, 66have interengaging teeth 68 which are free to separate axially when thedriving attachment 38 is removed from the tool body 32. When theattachment is assembled on the tool body, the clutch teeth 68interengage to effectively. drivably couple the spindle 20 to the motorshaft 34.

As noted earlier, the fastener strip pack 24 comprises a number offasteners 12, in this instance screws, joined side by side to thecarrier tape or strip 26. This carrier strip may be constructed ofvarious materials and in various ways but preferably comprises a friableplastic, such a as polystyrene or polyurethane. One method offabricating such a fastener strip pack is disclosed in my prior U.S.Pat. No. 3,303,632. The shanks of the screws 12 extend through thecarrier strip in such a way that the screw heads are exposed above thestrip and the screw points are exposed below the strip.

The fastener infeed means 28 comprises an infeed magazine 70. Thisinfeed magazine has a pair of spaced parallel walls 72 definingtherebetween an intervening guideway 74. Adjacent one end, the magazinewalls arch outwardly away from one another to define a generallycylindrical sleevelike formation 76 containing a bore 78. integrallyjoined to the upper edges of the walls in concentric relation to thesleeve formation 76 is a mounting plate 80. This mounting plate issecured by the screws 48 to the lower inclined face 52 of the guide tipmember 50 in such a way that the magazine bore 78 is coaxially alignedwith the guide bore 18. The magazine 70 extends upwardly at an acuteangle from the guide bore, as shown.

From this description, it is evident that the magazine bore 78effectively forms a continuation of the guide bore 18. The magazineguideway 74 opens at one end to the bore 78, through one side of thebore, as shown.

The magazine guideway 74 is laterally dimensioned to receive, with asliding fit, the fastener carrier strip 26, such that the strip and itsattached fasteners or screws 12 can slide along the guideway toward theguide bore 78. The screw heads project laterally beyond the sides of thecarrier strip and rest slidably on the upper edges of the magazinesidewalls 72 to vertically support the screws and carrier strip. At thispoint, it is significant to note that the longitudinal axes of thescrews are inclined relative to the longitudinal axis of the carrierstrip at an acute angle approximately equal to the angle between theguide bore 18, 78 and the longitudinal axis of the magazine guideway 74,such that the screws are vertically stepped and parallel the guide bore,as shown.

Positioned within the magazine 70, behind the fastener strip pack 24, isa spring-loaded follower 82 which urges the pack inwardly toward theguide bore 18, 78. This follower includes a follower plate 84 whichslides in the magazine guideway 74. Joined to the upper and lower edgesof the plate are flanges 86, 88 which extend laterally across the upperand lower edges of one magazine sidewall 72 and then toward one anotheracross the outer surface of this sidewall so as to form, in effect, arectangular bearing sleeve which slidably supports the follower plate 84on the magazine 70 for movement along its guideway 74. The outer ends ofthe magazine walls 72 are joined by an intervening block 90 which closesthe outer end of the guideway, whereby the follower plate 84 iscaptivated in the guideway.

Joined to the upper edge of the follower plate 84 and projectinglaterally from the plate in a direction opposite to the plate flanges86, 88 is an arm 92. The outer end of this arm turns downwardly at rightangles and projects into the space between the adjacent magazinesidewall 72 and a plate 94 secured to the later wall. Disposed betweenthe wall and plate is a guide 95 which extends longitudinally of themagazine 70, intermediate the upper and lower edges of the plate 94 andthe adjacent magazine sidewall 72. The inner end of this guide, that is,the end of the guide adjacent the guide bore 18, 78, is rounded, asshown. Below the outer end of the guide is a tension spring 96, theouter end of which is attached to the magazine, as shown. A flexiblemetal band 98 is secured at its ends to the opposite end of the spring96 and to the follower plate arm 92, respectively, and extends inwardlyfrom the arm along the upper side of the guide 95, then around thecurved inner end of the guide, and finally outwardly along the undersideof the guide to the spring 96. The underside of the guide is relieved toaccommodate the spring, as shown. It is now evident, therefore, that thespring 96 acts through the band 98 to urge the follower plate 84inwardly toward the guide bore 18, 78. Rising from the rear end of thefollower plate is a finger-piece or grip 100 by which the plate may beretracted outwardly along the guideway against the action of the spring96. The follower plate is thus retracted to permit insertion or loadingof a fastener strip pack 24 into the magazine 70 in front of thefollower plate. If desired, means (not shown) may be provided forreleasably retaining the follower plate in its retracted position tofacilitate loading of the magazine.

The inner leading edge of the follower plate 84 engages the rear end ofthe fastener strip pack 24 so as to urge the latter inwardly along themagazine guideway 74 toward the guide bore 18, 78. Preferably, thisleading plate edge is contoured, as shown, to engage the protrudingupper and lower ends of the trailing or outermost screw 12 in the pack.

In use of the present tool, the latter is held by the tool body 30.Initially, the forward guide sleeve 42 will be extended forwardly by theguide spring 56 to the position of FIG. 1, wherein the tool spindle 20occupies its retracted position relative to the guide 16. In thisretracted position, the spindle clears the lateral opening 78a to theguide bore 18, 78 through which the magazine guideway 74 opens to thebore. The

nificance is the fact that the first or leading screw 12 is spaced fromthe leading end of the carrier strip to be coaxially disposed in theguide bore when inward movement of the strip is terminated-a by abutmentof the strip against the far wall of the bore. Slots in the lowerportion of sleeve 76 of the tool guide (FIG. 6) provide a view to permitaccurate spotting of the screw into the workpiece, this'being being ofparticular importance with a predrilled workpiece. The tool is thenpressed against the workpiece 14 to retract the forward guide sleeve 42rearwardly relative to the rear guide sleeve 40 and thereby effectrelative forward movement of the spindle through its driving stroke.The'spindle drive motor is simultaneously energized to drive the spindlein rotation. The screw driver tip 58 on the spindle then mates with thescrew in driving position to drive the latter in rotation andsimultaneously advance the screw forwardly through the guide bore intothe workpiece. During this driving stroke, the. friable carrier strip 26is sheared and/or fragmented to separate the screw from the strip. Afterthe screw has been driven the tool is removed from the workpiece topermit return of the parts to their original position brrro; 1. At thispoint, the follower plate 84 again advances the fastener strip pack 24inwardly through the fastener magazine 70 to locate the next screw indriving position.

Pivotally mounted in a slot in the front end of the guide 16 is aspring-loaded retainer plate 102. This plate exerts a resilient lateralforce against each screw 12 as the latter is initially driven forwardlyfrom the carrier strip 26 and serves to retain the screw and screwdriver tip 58 in driving engagement until the screw engages theworkpiece.

The modified fastener driving too] 10a illustrated in FIG. 7 isidentical to the tool 10, just described, except that the front guide16a of the tool is equipped with adjustable supporting legs 104a whichengage the workpiece to permit driving of relatively long screws, and toprovide for viewing the workpiece and screw to assist in accuratespotting of the screw. These adjustable supporting legs may comprisescrews which are threaded in the front end of the guide, as shown.

While the invention has been disclosed in connection withcertainillustrative embodiments thereof, it will be evident to thoseversed in the art that various modifications of the inven tion arepossible within the spirit and scope of the following claims.

I Iclaim:

1. A fastener driving tool comprising:

a guide having front andrear ends and a longitudinal bore 1 openingthrough said front end;

v a fastener driving spindle movable longitudinally in said bore; 7means for moving said spindle longitudinally in said bore throughalternate rearward retraction and forward driving strokes; afastenerstrip pack including a'relatively longitudinally rigid carrierstrip, and a number of fasteners secured to 5 said strip inlongitudinally spaced relation therealong with the longitudinal axes ofsaid fasteners extending transverse to the longitudinal axis of saidstrip; infeed means for feeding said carrier strip longitudinally intosaid guide bore through one side of said bore following each retractionstroke of said spindle to locate the currently leading fastener on saidstrip in coaxial driving position within said bore in front of saidspindle, said infeed means comprising an infeed magazine attached to andextending laterally from said guide and containing a guideway opening atone end laterally to said guide bore.

said carrier strip being slidably contained within said I guideway forlongitudinal movement along said guideway, and spring-loaded followermeans engaging the trailing end of said strip for urging said striptoward said 2 bore;

said spindle comprising aforward driving tip for separating the leadingfastener currently in driving position from said carrier strip anddriving said leading fastener forwardly through said bore into aworkpiece positioned in front of said bore during the following drivingstroke of said spindle; and j said carrier strip comprising a friablematerial which is sheared and fragmented by said spindle during eachdriving stroke of said spindle to effect release from said carrier stripof the leading fastener currently in driving position within said guidebore.

2. A tool according to claim 1 wherein: said follower means comprises afollower slidable in said guideway behind said carrier strip, and aspring extending along one side of said guideway externally thereof andsecured at one end to said A magazine and at the other end to saidfollower.

3. A tool according to claim 2 wherein: said means for moving saidspindle comprises a body at the rear of said guide, means supportingsaid guide on said body for relative axial movement relative to saidbody and spindle, said infeed means moving in unison with said guide,means on the front end of said guide engageable with a workpiecepositioned in front of said guide, whereby forward pressure on said bodymoves said body forwardly relative to said spindle to move said spindlethrough its driving stroke relative to said guide, and a spring actingbetween said guide and body for urging a said guide forwardly relativeto said body.

4. A tool according to claim 3 wherein: said mounting means comprises asleeve surrounding said spindle and secured at one end to said body, andmeans joining the other end of said guide and sleeve in slidabletelescoping relation.

5. A tool according to claim 4 wherein: said fasteners extend throughsaid carrier strip in such a way that the ends of each fastener areexposed beyond opposite sides of said carrier strip; and the leading endof said follower adjacent said carrier strip spaced shoulders engagingthe protruding ends of the adjacent trailing fastener in said carrierstrip.

1. A fastener driving tool comprising: a guide having front and rearends and a longitudinal bore opening through said front end; a fastenerdriving spindle movable longitudinally in said bore; means for movingsaid spindle longitudinally in said bore through alternate rearwardretraction and forward driving strokes; a fastener strip pack includinga relatively longitudinally rigid carrier strip, and a number offasteners secured to said strip in longitudinally spaced relationtherealong with the longitudinal axes of said fasteners extendingtransverse to the longitudinal axis of said strip; infeed means forfeeding said carrier strip longitudinally into said guide bore throughone side of said bore following each retraction stroke of said spindleto locate the currently leading fastener on said strip in coaxialdriving position within said bore in front of said spindle, said infeedmeans comprising an infeed magazine attached to and extending laterallyfrom said guide and containing a guideway opening at one end laterallyto said guide bore, said carrier strip being slidably contained withinsaid guideway for longitudinal movement along said guideway, andspring-loaded follower means engaging the trailing end of said strip forurging said strip toward said bore; said spindle comprising a forwarddriving tip for separating the leading fastener currently in drivingposition from said carrier strip and driving said leading fastenerforwardly through said bore into a workpiece positioned in front of saidbore during the following driving stroke of said spindle; and saidcarrier strip comprising a friable material which is sheared andfragmented by said spindle during each driving stroke of said spindle toeffect release from said carrier strip of the leading fastener currentlyin driving position within said guide bore.
 2. A tool according to claim1 wherein: said follower means comprises a follower slidable in saidguideway behind said carrier strip, and a spring extending along oneside of said guideway externally thereof and secured at one end to saidmagazine and at the other end to said follower.
 3. A tool according toclaim 2 wherein: said means for moving said spindle comprises a body atthe rear of said guide, means supporting said guide on said body forrelative axial movement relative to said body and spindle, said infeedmeans moving in unison with said guide, means on the front end of saidguide engageable with a workpiece positioned in front of said guide,whereby forward pressure on said body moves said body forwardly relativeto said spindle to move said spindle through its drivinG stroke relativeto said guide, and a spring acting between said guide and body forurging a said guide forwardly relative to said body.
 4. A tool accordingto claim 3 wherein: said mounting means comprises a sleeve surroundingsaid spindle and secured at one end to said body, and means joining theother end of said guide and sleeve in slidable telescoping relation. 5.A tool according to claim 4 wherein: said fasteners extend through saidcarrier strip in such a way that the ends of each fastener are exposedbeyond opposite sides of said carrier strip; and the leading end of saidfollower adjacent said carrier strip spaced shoulders engaging theprotruding ends of the adjacent trailing fastener in said carrier strip.